Image capture method and systems to preserve apparent contrast of an image

2. The method of claim 1, wherein the transforming corrects the image data derived from the first plurality of image data before the mapping through the tone mapping function such that the tone mapping function operates on data derived from the transforming and wherein the tone mapping function compresses a dynamic range of the image to match the gamut and luminance parameters of the target display.

3. The method of claim 1 wherein the estimated ambient light level is saved as metadata with image data of the image, and wherein tone mapping through the tone mapping function is performed on pixel values scaled to absolute scene light levels and wherein the camera specific parameter is a constant value derived empirically from the camera calibration.

4. The method of claim 3 wherein the metadata is used to compensate flare in the image, where the flare compensation is a function of a value representing the estimated ambient light level.

6. The method of claim 1 wherein the dynamically measured ambient light of the viewing environment is measured by an ambient light sensor that is integrated into the target display so that the OOTF is dynamically controlled by the output of the ambient light sensor.

9. The method of claim 1 wherein the OOTF preserves the apparent contrast by adjusting image data in relatively dark regions of the image to reduce contrast in the relatively dark regions when the estimated ambient light level has a higher luminance than the luminance of the viewing environment, and the OOTF preserves the apparent contrast by adjusting image data in relatively dark regions of the image to increase contrast in the relatively dark regions of the image when the estimated ambient light level has a lower luminance than the luminance of the viewing environment.

10. The method of claim 1 wherein the tone mapping function includes local tone mapping in one or more regions of the image, and the local tone mapping is used during mapping to create a standard dynamic range, SDR, image from the image and wherein the metadata is saved with the SDR image for use in reconstructing a high dynamic range, HDR, image via inverse mapping.

11. The method of claim 10 wherein the metadata is used to calculate multivariate, multiple regression, MMR, coefficients for inverse mapping from the SDR image to the HDR image and wherein the metadata is adjusted by the tone mapping to an intermediate set of metadata to guide downstream processing of a tone mapped image.

12. An apparatus comprising a processing system and memory and configured to perform the method in claim 1.

13. A non-transitory machine-readable storage storing executable program instructions which when executed by a machine cause the machine to perform the method of claim 1.